directshow USB摄像头预览
//指定视频采集设备的友好名字，为它创建一个FilterIBaseFilter*CTestPreviewDlg::CreateVideoDevice(constchar*inFriendlyName){returnCreateHardwareFilter(CLSID_VideoInputDeviceCategory,inFriendlyName);}//根据设备的友好名字，创建一个代表该设备的FilterIBaseFilter*CTestPreviewDlg::CreateHardwareFilter(GUIDinCategory,constchar*inFriendlyName){//创建一个系统枚举组件对象